The song is called Sad Pacific.

According to qq music query, one step forward is dusk, one step back is life, and Ren Xianqi’s sad Pacific Ocean. Ren Xianqi released the music compilation album "Running to the Rainbow" in 1990 and debuted as a singer. In 1991, he made his first appearance in the movie Soldiers Catching Robbers.

Part of the lyrics excerpt Nakajima Miyuki, is it really cruel to leave, or is it shameful to be gentle, or is it okay to be lonely.